U.S. Pat. No. 3,004,647 to Everett H. Andrus and George M. Coon and U.S. Pat. No. 3,509,976 to George M. Coon disclose control systems for limiting a machine, such as a punch press, to a single cycle of operation and having provision for insuring that a failure of any of the various control components in the system cannot result in an unexpected repeat stroke of the machine which might endanger the operator.